/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2008-2011, Salzburg Research. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * - Neither the name of the KiWi Project nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * Contributor(s):
 * Stefan
 *
 * File Info:
 * User: Stefan
 * Date: 2011/01/27
 * Time: 15:36
 *
 * Project: KiWi2, kiwi-core module
 */

package kiwi.core.services.io;

import kiwi.core.api.config.ConfigurationService;
import kiwi.core.api.io.KiWiParser;
import kiwi.core.exception.ParsingException;
import org.hibernate.engine.jdbc.ReaderInputStream;
import org.openrdf.model.ValueFactory;
import org.openrdf.repository.Repository;
import org.openrdf.repository.RepositoryConnection;
import org.openrdf.repository.RepositoryException;
import org.openrdf.repository.sail.SailRepository;
import org.openrdf.rio.RDFHandlerException;
import org.openrdf.rio.RDFParseException;
import org.openrdf.rio.RDFParser;
import org.openrdf.rio.helpers.StatementCollector;
import org.openrdf.sail.memory.MemoryStore;
import org.slf4j.Logger;

import javax.inject.Inject;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;

/**
 * A parser for RDF-Quads file. It is similar to the RDFXML Syntax. Base for this realisation is the RDFa Quads
 * extension. New is the graph:graph attribute which describe a Context. It is not complete backward to RDFXML
 * Example:
 *
 * <rdf:Description rdf:about="http://www.w3.org/TR/rdf-syntax-grammar">
 * <ex:editor graph:graph="http://example.org/graph1">
 *   <rdf:Description>
 *     <ex:homePage rdf:resource="http://purl.org/net/dajobe/"/>
 *     <ex:fullName>Dave Beckett</ex:fullName>
 *   </rdf:Description>
 * </ex:editor>
 * <dc:title graph:graph="http://example.org/graph2">RDF/XML Syntax Specification (Revised)</dc:title>
 *</rdf:Description>
 *
 * User: srobert
 */
public class RdfQuadsParser implements KiWiParser {

    @Inject
    private Logger log;

    @Inject
    private ConfigurationService configurationService;

    private ValueFactory valueFactory;

    private String baseURI = "";

	private static final List<String> MIMETYPES;
	static {
		MIMETYPES = new ArrayList<String>();
		MIMETYPES.add("application/quads+xml");
	}

	@Override
	public List<String> getAcceptFormats() {
		return MIMETYPES;
	}

    /**
     * Parse the triple data contained in the string passed as argument and return a Sesame in-memory repository for
     * further processing.
     *
     * @param data a string containing the triple data in the format implemented by this parser
     * @return a Sesame in-memory repository containing the parsed triple data
     * @throws kiwi.core.exception.ParsingException
     *          if the string passed as argument does not have the right format
     */
    @Override
    public Repository parseTriples(String data) throws ParsingException {

        try {
            return parseTriples(new StringReader(data));
        } catch (IOException e) {
            log.error("I/O error while trying to read from string, this should never happen", e);
            throw new ParsingException("I/O error while trying to read from string", e);
        }

    }

    /**
     * Parse the triple data contained in the reader passed as argument and return a Sesame in-memory repository for
     * further processing.
     *
     * @param reader a Reader from which the triple data in the format implemented by this parser can be read
     * @return a Sesame in-memory repository containing the parsed triple data
     * @throws kiwi.core.exception.ParsingException
     *          if the data read from the Reader does not have the right format
     */
    @Override
    public Repository parseTriples(Reader reader) throws ParsingException, IOException {
        Repository repository = new SailRepository(new MemoryStore());
        RepositoryConnection con = null;
        try {
            repository.initialize();
            con = repository.getConnection();

            StatementCollector collector = new StatementCollector();

            RDFParser parser = new RdfQuadsReader();
            parser.setRDFHandler(collector);
            parser.setVerifyData(false);
            parser.setStopAtFirstError(false);
            parser.parse(new ReaderInputStream(reader), configurationService.getBaseUri());

            con.add(new ArrayList(collector.getStatements()));
            con.commit();

        } catch (RepositoryException e) {
            log.error("repository error while establising connection to memory repository, should not happen!", e);
        } catch (RDFParseException e) {
            log.error("error while parsing input data in RDF/XML format", e);
            throw new ParsingException("Error while parsing input data in RDF/XML format", e);
        } catch (RDFHandlerException e) {
            log.error("error while parsing input data", e);
        }


        return repository;
    }

    /**
     * Parse the triple data contained in the reader passed as argument and return a Sesame in-memory repository for
     * further processing.
     *
     * @param in an InputStream from which the triple data in the format implemented by this parser can be read
     * @return a Sesame in-memory repository containing the parsed triple data
     * @throws kiwi.core.exception.ParsingException
     *          if the data read from the stream does not have the right format
     */
    @Override
    public Repository parseTriples(InputStream in) throws ParsingException, IOException {
        Repository repository = new SailRepository(new MemoryStore());
        RepositoryConnection con = null;
        try {

            repository.initialize();
            con = repository.getConnection();

            StatementCollector collector = new StatementCollector();

            RDFParser parser = new RdfQuadsReader();
            parser.setRDFHandler(collector);
            parser.setVerifyData(false);
            parser.setStopAtFirstError(false);
            parser.parse(in, configurationService.getBaseUri());

            con.add(new ArrayList(collector.getStatements()));
            con.commit();

        } catch (RepositoryException e) {
            log.error("repository error while establising connection to memory repository, should not happen!", e);
        } catch (RDFParseException e) {
            log.error("error while parsing input data in RDF/XML format", e);
            throw new ParsingException("Error while parsing input data in RDF/XML format", e);
        } catch (RDFHandlerException e) {
            log.error("error while parsing input data", e);
        } finally {
            try {
                con.close();
            } catch(Exception e) {}
        }

        return repository;
    }

}

